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Stem Cells International
Volume 2014 (2014), Article ID 101349, 8 pages
http://dx.doi.org/10.1155/2014/101349
Research Article

DNA Methylation Is Involved in the Expression of miR-142-3p in Fibroblasts and Induced Pluripotent Stem Cells

1Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
2Division of Stem Cell Therapy, Center for Stem Cell Biology and Regenerative Medicine, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan

Received 11 August 2014; Revised 4 November 2014; Accepted 14 November 2014; Published 2 December 2014

Academic Editor: Chia-Lin Wei

Copyright © 2014 Siti Razila Abdul Razak et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

MicroRNAs are differentially expressed in cells and regulate multiple biological processes. We have been analyzing comprehensive expression patterns of microRNA in human and mouse embryonic stem and induced pluripotent stem cells. We determined microRNAs specifically expressed in these pluripotent stem cells, and miR-142-3p is one of such microRNAs. miR-142-3p is expressed at higher levels in induced pluripotent stem cells relative to fibroblasts in mice. Level of expression of miR142-3p decreased during embryoid body formation from induced pluripotent stem cells. Loss-of-function analyses of miR-142-3p suggested that miR-142-3p plays roles in the proliferation and differentiation of induced pluripotent stem cells. CpG motifs were found in the 5′ genomic region of the miR-142-3p; they were highly methylated in fibroblasts, but not in undifferentiated induced pluripotent stem cells. Treating fibroblasts with 5-aza-2′-deoxycytidine increased the expression of miR-142-3p significantly and reduced methylation at the CpG sites, suggesting that the expression of miR-142-3p is suppressed by DNA methylation in fibroblasts. Luciferase analysis using various lengths of the 5′ genomic region of miR142-3p indicated that CpGs in the proximal enhancer region may play roles in suppressing the expression of miR-142-3p in fibroblasts.